A quick note to make about Toriyama - regardless of people's feelings of him - he IS a very successful project manager. He's directed 6 releases in a span of 13 years, on a variety of platforms (handhelds and home consoles) and a variety of budgets (small, medium and large). His biggest stumble seems to have been in the delivery time of the large-budget FF13 project, and he effectively used assets from that game to quickly push out medium budget sequels. Of everything he's made, XIII-2 and X-2 are probably my favorites.
It's hard to predict at this point. I was so sure he'd be directing FF7R but if Nomura is already on the gig I'm not sure if they'd toss him in as a co-director or something else.
As for the others, I'd rule them out based on their liklihood.... yet Siliconera has reported on a new Front Mission, and Verendus has said there is both a FFX spin-off and a new Parasite Eve in the works (I pretty much take Verendus' hints as the truth at the moment).
Basically all 4 on your list are a possibility, and that's why I assumed you put it together with those 4 titles shown.
That said, it'd be a roll of the dice between a FFX game and Parasite Eve. I'll choose Parasite Eve (for now).